The present invention relates generally to an air break disconnect switch for high voltage electrical applications and, more particularly, to an in-line high voltage air break disconnect switch that mounts in-line with the transmission line conductor without the need of a group operated switch with associated ground supported mounting structure. Such an in-line high voltage disconnect switch hangs from and is supported by its associated transmission line.
One example of such an in-line high voltage disconnect switch is a vertical break disconnect switch currently manufactured and sold by Cleaveland/Price Inc., of Trafford, Pa., the present Assignee, as a type ILO-C, Hookstick Operated In-Line Transmission Switch. The switch is described in Cleaveland/Price Bulletin DB-1021611, entitled “Type ILO-C Hookstick Operated In-Line Transmission Switch 69 kV-230 kV 1200 A.”. The switch is rated 69 kV-230 kV, 1200 amperes. The Cleaveland/Price Inc. type ILO-C In-Line high voltage disconnect switch utilizes a manually operated hookstick for engaging an operating eye ring attached to the breakjaw end of the switch blade of the switch. The hookstick when engaged with the operating ring imparts rotation to the hinge end of the switch blade for opening and closing of the switch. The Cleaveland/Price Inc. type ILO-C In-Line high voltage disconnect switch is a single phase switch and is versatile and can serve many functions on a three phase system. The switch can be used to sectionalize long transmission lines, disconnect lines from substations, serve as a line tap switch, and serve as a temporary maintenance switch, for example. The Cleaveland/Price Inc. type ILO-C In-Line high voltage disconnect switch saves significant installation costs compared to a non-in-line switch installed via direct ground support mounting structure. The Cleaveland/Price Inc. type ILO-C high voltage disconnect switch allows for easy, cost efficient sectionalizing of high voltage transmission lines and isolation in high voltage substations. As a result of this, the type ILO-C In-Line high voltage disconnect switch has been used by electric utilities for many years to isolate transmission and substation circuits.
U.S. Pat. No. 9,881,755 B1 by Charles M. Cleaveland and issued to Cleaveland/Price Inc., the present assignee on Jan. 30, 2018, discloses a communication system controlled in-line motorized high voltage disconnect switch. The switch includes an elongated strain insulator supporting an elongated rotating switch blade having a hinge contact end and a break jaw contact end. The rotating switch blade is rotatable about a hinge pin at the hinge contact end during opening and closing of the switch. The switch includes a motor connected to an output shaft to cause the hinge end of the switch blade to rotate when energized to open or close the switch. A communication system actuates the motor to cause the switch to open and close as desired. The communication system may include a number of communication devices including a portable wireless hand-held control box for communicating with a switch mounted radio. The said Cleaveland/Price Inc. patent discloses embodiments of a vertical break and a side break in-line motorized high voltage disconnect switch. Both the vertical break and side break switches include an elongated switch blade that is rotatable at one end of the switch blade, i.e., about the hinge end. Reference is also made to U.S. Pat. No. 9,966,207 B1 by Charles M. Cleaveland and issued to Cleaveland/Price Inc., the present assignee on May 8, 2018, which also discloses a communication system controlled in-line motorized high voltage disconnect switch. The said U.S. Pat. No. 9,881,755 B1 and the said U.S. Pat. No. 9,966,207 B1 are both incorporated herein by reference in their entireties as though fully set forth.
It has been found that as such in-line motorized side break switches as disclosed in U.S. Pat. Nos. 9,881,755 B1 and 9,966,207 B1 go up in voltage, i.e., above 138 kV, it is difficult to keep the weight of the switch blade from putting an excessive torsional load on the transmission line which results in “rolling of the switch” mounted to the suspension insulator. This is caused by the side break switch blade embodiment, above 138 kV, opening generally horizontally to the ground and creating an excessive torque causing the “rolling of the switch”. It is the object of the present invention to provide a solution to this problem.